MYSM1-AR complex-mediated repression of Akt/c-Raf/GSK-3β signaling impedes castration-resistant prostate cancer growth

MYSM1 acts as a novel co-activator of ERα to confer antiestrogen resistance in breast cancer

Endocrine resistance is a crucial challenge in estrogen receptor alpha (ERα)-positive breast cancer (BCa). Aberrant alteration in modulation of E2/ERα signaling pathway has emerged as the putative contributor for endocrine resistance in BCa. Herein, we demonstrate that MYSM1 as a deubiquitinase participates in modulating ERα action via histone and non-histone deubiquitination. MYSM1 is involved in maintenance of ERα stability via ERα deubiquitination. MYSM1 regulates relevant histone modifications on cis regulatory elements of ERα-regulated genes, facilitating chromatin decondensation. MYSM1 is highly expressed in clinical BCa samples. MYSM1 depletion attenuates BCa-derived cell growth in xenograft models and increases the sensitivity of antiestrogen agents in BCa cells. A virtual screen shows that the small molecule Imatinib could potentially interact with catalytic MPN domain of MYSM1 to inhibit BCa cell growth via MYSM1-ERα axis. These findings clarify the molecular mechanism of MYSM1 as an epigenetic modifier in regulation of ERα action and provide a potential therapeutic target for endocrine resistance in BCa.

Emerging proteins involved in castration‑resistant prostate cancer via the AR‑dependent and AR‑independent pathways (Review)

Despite achieving optimal initial responses to androgen deprivation therapy, most patients with prostate cancer eventually progress to a poor prognosis state known as castration‑resistant prostate cancer (CRPC). Currently, there is a notable absence of reliable early warning biomarkers and effective treatment strategies for these patients. Although androgen receptor (AR)‑independent pathways have been discovered and acknowledged in recent years, the AR signaling pathway continues to play a pivotal role in the progression of CRPC. The present review focuses on newly identified proteins within human CRPC tissues. These proteins encompass both those involved in AR‑dependent and AR‑independent pathways. Specifically, the present review provides an in‑depth summary and analysis of the emerging proteins within AR bypass pathways. Furthermore, the significance of these proteins as potential biomarkers and therapeutic targets for treating CRPC is discussed. Therefore, the present review offers valuable theoretical insights and clinical perspectives to comprehensively enhance the understanding of CRPC.

MYSM1 induces apoptosis and sensitizes TNBC cells to cisplatin via RSK3-phospho-BAD pathway

Breast cancer is one of the leading causes of mortality among women. Triple-negative breast cancer (TNBC) is responsible for a large percentage of all breast cancer deaths in women. This study demonstrated the function of Myb-like, SWIRM, and MPN domains 1 (MYSM1), an H2A deubiquitinase (DUB), in TNBC. MYSM1 expression was drastically decreased in breast cancer, especially in TNBC, suggesting a potential anticancer effect. Overexpressing and suppressing MYSM1 expression in TNBC cell lines led to significant biological changes in cell proliferation. Furthermore, MYSM1 overexpression increased cisplatin-induced apoptosis, which might be attributed to RSK3 inactivation and the subsequently decreased phosphorylation of Bcl-2 antagonist of cell death (BAD) (Ser 112). The findings suggest that MYSM1 is a potential target for regulating cell apoptosis and suppressing resistance to cisplatin in TNBC.

MYSM1 inhibits human colorectal cancer tumorigenesis by activating miR-200 family members/CDH1 and blocking PI3K/AKT signaling

Background

Histone epigenetic modification disorder is an important predisposing factor for the occurrence and development of many cancers, including colorectal cancer (CRC). The role of MYSM1, a metalloprotease that deubiquitinates monoubiquitinated histone H2A, in colorectal cancer was identified to evaluate its potential clinical application value.

Methods

MYSM1 expression levels in CRC cell lines and tumor tissues were detected, and their associations with patient survival rate and clinical stage were analyzed using databases and tissue microarrays. Gain- and loss-of-function studies were performed to identify the roles of MYSM1 in CRC cell proliferation, apoptosis, cell cycle progression, epithelial-mesenchymal transition (EMT) and metastasis in vitro and in vivo. ChIP, rescue assays and signal pathway verification were conducted for mechanistic study. Immunohistochemistry (IHC) was used to further assess the relationship of MYSM1 with CRC diagnosis and prognosis.

Results

MYSM1 was significantly downregulated and was related to the overall survival (OS) of CRC patients. MYSM1 served as a CRC suppressor by inducing apoptosis and inhibiting cell proliferation, EMT, tumorigenic potential and metastasis. Mechanistically, MYSM1 directly bound to the promoter region of miR-200/CDH1, impaired the enrichment of repressive H2AK119ub1 modification and epigenetically enhanced miR-200/CDH1 expression. Testing of paired CRC patient samples confirmed the positive regulatory relationship between MYSM1 and miR-200/CDH1. Furthermore, silencing MYSM1 stimulated PI3K/AKT signaling and promoted EMT in CRC cells. More importantly, a positive association existed between MYSM1 expression and a favorable CRC prognosis.

Conclusions

MYSM1 plays essential suppressive roles in CRC tumorigenesis and is a potential target for reducing CRC progression and distant metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02106-2.

Long noncoding RNA LINC00963 induces NOP2 expression by sponging tumor suppressor miR-542-3p to promote metastasis in prostate cancer

Metastatic disease caused by castration-resistant prostate cancer (CRPC) is the principal cause of prostate cancer (PCa)-related mortality. CRPC occurs within 2-3 years of initiation of androgen deprivation therapy (ADT), which is an important factor of influencing PCa metastasis. Recent studies have revealed that non-coding RNAs in PCa can enhance metastasis and progression, while the mechanisms are still unclear. In this study, we reported that the long noncoding RNA-LINC00963 was increased in CRPC tissues and promoted migration of PCa cells in vitro and their metastasis in vivo. High levels of LINC00963 significantly decreased tumor suppressor miR-542-3p, whose levels in metastasis tissues were low compared to those in non-metastasis tissues. LINC00963 promotes and miR-542-3p inhibits metastasis. Furthermore, the expression levels of LINC00963 and miR-542-3p were positively and negatively associated with the expression of NOP2. We demonstrated that NOP2 promoted PCa by activating the epithelial-mesenchymal transition (EMT) pathway. For specific mechanism, dual luciferase reporter assays showed that miR-542-3p directly binds to both 3'-untranslated region (UTR) of LINC00963 and NOP2 mRNA. Taken together, our results show that LINC00963 acts as an inducer of PCa metastasis by binding miR-542-3p, thereby promoting NOP2. This axis may have diagnostic and therapeutic potential for advanced PCa.

VHL mutation-mediated SALL4 overexpression promotes tumorigenesis and vascularization of clear cell renal cell carcinoma via Akt/GSK-3β signaling

Background

Although ongoing development of therapeutic strategies contributes to the improvements in clinical management, clear cell renal cell carcinoma (ccRCC) deaths originate mainly from radiochemoresistant and metastatic disease. Transcription factor SALL4 has been implicated in tumorigenesis and metastasis of multiple cancers. However, it is not known whether SALL4 is involved in the pathogenesis of ccRCC.

Methods

Analyses of clinical specimen and publicly available datasets were performed to determine the expression level and clinical significance of SALL4 in ccRCC. The influence of SALL4 expression on ccRCC tumor growth, metastasis and vascularity was evaluated through a series of in vitro and in vivo experiments. Western blotting, immunofluorescence staining and integrative database analysis were carried out to investigate the underlying mechanism for SALL4-mediated oncogenic activities in ccRCC.

Results

SALL4 expression was increased in ccRCC and positively correlated with tumor progression and poor prognosis. SALL4 could promote ccRCC cell proliferation, colony formation, cell cycle progression, migration, invasion and tumorigenicity and inhibit cell senescence. Further investigation revealed a widespread association of SALL4 with individual gene transcription and the involvement of SALL4 in endothelium development and vasculogenesis. In the context of ccRCC, SALL4 promoted tumor vascularization by recruiting endothelial cells. In addition, we found that SALL4 could exert its tumor-promoting effect via modulating Akt/GSK-3β axis and VEGFA expression. VHL mutation and DNA hypomethylation may be involved in the upregulation of SALL4 in ccRCC.

Conclusions

Overall, our results provide evidence that upregulated SALL4 can function as a crucial regulator of tumor pathogenesis and progression in ccRCC, thus offering potential therapeutic strategies for future treatment.